This invention relates to an improved catalyst system for the polymerization of ethylene to form ethylene homopolymers and interpolymers of ethylene and other .alpha.-olefins and/or diolefins.
U.S. Pat. No. 3,379,706 discloses that certain .pi. allyl metal compounds have activity as polymerization, including oligomerization, catalysts. With respect to the polymerization of ethylene, it is disclosed, for example, that tris .pi.-allyl chromium (.pi. allyl chromium [III]) will polymerize ethylene to form linear polyethylenes having infra-red spectra identical with the spectra of the so-called Ziegler polyethylenes at a level of productivity, however, in the order of only 5-36 grams of polymer per gram of chromium per hour.